The invention relates to an animal shearing machine.
Electrically operated animal shearing machines of different constructions have been known from the state of the art for a long time.
For example, DE 11 96 994 A describes an animal shearing machine which is driven by an electric motor. The housing of the device, which serves at the same time as a handle, has a shearing head at the front end. The shearing head consists of a stationary cutting comb and a movable cutting comb which oscillates back and forth in relation to the stationary cutting comb. The movable cutting comb is held and driven by a fork which is movable back and forth about a joint. The drive of the movable cutting comb is brought about by the use of an eccentric in a manner which is, in the meantime, well-known. With the aid of the eccentric, the rotational movement of a driving electric motor can be transformed into the desired oscillating movement of the shearing head. The eccentric engages for this purpose in a slot in the fork which is mounted so as to be movable. Since considerable drive moments are required in the case of animal shearing machines on account of the thickness of the hair and the density of the coat of the animals, the drive moment of the electric motor used is transferred to the eccentric via a reduction gear. In the case of the animal shearing machine disclosed in DE 11 96 994 A, a spur gear is used for this purpose. The drive unit consisting of electric motor, gear, eccentric and oscillating fork is accommodated completely within the housing of the animal shearing machine. The electric motor is mounted in the housing in such a manner that the shaft of the electric motor is arranged in the direction of the longitudinal axis of the housing. Drive shaft and driven shaft of a spur gear extend parallel at a distance to one another. The axis of oscillation of the eccentric connected to the driven shaft of the spur gear is aligned approximately at right angles to the fork connected to the movable cutting comb.
The use of a spur gear does, however, entail certain disadvantages. Spur gears are, on the one hand, well known to be relatively loud. On the other hand, the spatial requirements for a spur gear are relatively large, for which reason the housing of the animal shearing machine cannot be constructed in accordance with the ergonomic points of view or requirements which apply today when a spur gear is used or the required reduction is not achieved. The spur gear shown in DE 11 96 994 A is, in addition, mounted on the housing in a complicated manner.
In the meantime, it is now common to use a worm gear instead of the spur gear. In this respect, the shaft of the electric motor is generally aligned such that it extends at an angle to the longitudinal axis of the housing. The worm wheel, which is connected to the driven shaft and the eccentric, is driven by the electric motor via a worm which is connected to the motor shaft. The axis of the eccentric connected to the worm wheel is approximately at right angles to the longitudinal axis of the housing and, as a result, extends approximately parallel to the axis of oscillation of an oscillating lever which is used in the meantime instead of the fork described in DE 11 96 994 A in order to drive the movable cutting comb of the shearing head. It is also no longer obligatory to connect the oscillating lever and cutting comb rigidly to one another but rather they are normally in entraining engagement.
The advantages of a worm gear include, above all, a high possible reduction with low space requirements as well as a low level of noise during operation. Worm gears are, in addition, of a relatively simple construction. Occasionally, however, significant problems do result during the use of a worm gear. For example, worm gears have a high sliding friction which leads to considerable wear and tear and considerable heating up. As a result, the degree of efficiency of the overall drive unit is relatively bad. The considerable heating up leads to the equipment not being operable on a continuous basis and, therefore, interruptions become necessary since the equipment becomes too hot both for the person as well as for the animal. As a result of the low degree of efficiency it is also difficult to realize battery-driven animal shearing machines since the service life of a battery of a justifiable size for the shearing procedure is not adequate.
It is, therefore, the object of the present invention to provide an animal shearing machine which operates with better energy efficiency and is, therefore, also suitable for battery operation with adequately long operating times.